Oh h1 is a little logic game created by Q42. It was created by Martin Kool. The concept is also known as Takuzu or Binairo.
Three adjacent tiles of the same color in a row or column isn't allowed. Rows and columns have an equal number of each color. No two rows and no two columns are the same.
Source: The Game Website.
Players can pick the size of the puzzle (4x4, 8x8). Each puzzle starts with a few fixed colored tiles. It's up to the player to correctly determine the colors of the rest the tiles.